Shockproof holding device



1950 c. D. HAYWARD SHOCKPROOF HOI DING DEVICE Original Filed Jan. 10,- 1944 Inventor: Claude D. Hayward, by W His Attorney.

was Jan. 24, 1950 2,495,833 SHOCKPROOF HOLDING DEVICE Claude D. Hayward,

General Electric New York Original application Jan Divided and Lansdowne, Pa., assignmto Company, a corporation of nary 10, 1944, Serial No. this application December 13, 1945, Serial No. 834,792

2 Claims. (Cl. 200-103) My invention relates to improvements in shock-proof holding devices and more particularly to shock-proof latching mechanisms for electric switches such as circuit breakers and the like.

Equipment for use for warcraft is subject to false operation because of mechanical shock due to the firing of guns on the craft and the explosion of enemy shells on or near the craft. These shocks are often of extreme severity, and they may be of a translational nature in any direction or. in consequence. of whipping of the supports of the equipment, they may be of a rotational character. Of course, a latching mechanism could be made proof against operation on any reasonable mechanical shock by restraining the motion of the moving parts with a sufllciently strong spring or by introducing a sufllcient amount of friction. This, however, is undesirable because the latching mechanism is thereby made very insensitive to operation in the intended manner. In other words, in order to overcome the restraining effect, a great force or power must be applied to the latching part in order to eflect operation of the device on the occurrence of abnormal circuit conditions. This great operating force or power is obtainable only at the sacrifice of sensitivity of response. Latching mechanisms have been made using rotating parts balanced about the axis of rotation so that a translational shock does not cause them to operate. Such arrangements, however, are not proof against operation on a rotational shock.

An object of my invention is to provide an improved arrangement for rendering devices proof against operation on either translational or rotational shock without materially interfering with their intended operational response. Another object of my invention is to provide an improved arrangement for rendering devices shock-proof by combining existing devices in accordance with the principle of my invention. These and other objects of my invention will appear in more detail hereinafter.

In accordance with my invention, I provide a two-position shock-proof holding device wherein two relatively movable-members are jointly and severally capable of maintaining the device in a given condition without altering said condition on the occurrence of shock and yet are capable of being moved in opposite directions so as jointly to effect a desired change in such condition of the device. Finally, in accordance with my invention. these members may be two armatures. two thermally responsive members, two toggles, two

' pivots 3 and 4, this latches or, in general, any two similar elements which are designed to respond to a given condition in an electrical circuit or in a fluid circuit or other physical condition that is subject to change.

This application is a division of my copending application, Serial No. 517,651, filed January 10, 1944, and subsequently abandoned, and assigned to the same assignee as this application.

My invention will be better understood from the following description when considered in connection with the accompanying sheet of drawings, and its scope will be pointed out in the appended claims.

In the accompanying sheet of drawings, Fig. 1 diagrammatically illustrates a shock-proof holding device embodying my invention; Fig. 2 is a diagrammatic view of a circuit breaker thermally responsive latching mechanism embodying my invention; Fig. 3 is an elevation, partly in section, of a fluid pressure operated latching mechanism embodying my invention; and Fig. 4 is an elevation of a circuit breaker toggle latching mechanism embodying my invention.

The shock-proof holding device or latching mechanism shown in Fig. 1 comprises two relatively freely movable elements such as two rotatably mounted armatures I and 2 respectively pivoted at 3 and 4. These armatures I and I are biased for movement in opposite directions by suitable similar means such as springs 5 and 6, respectively, to a holding position wherein latch engaging or hook portions land 8, respectively, jointly engage a suitable enlargement 9 on a member it which is to be held downward against a bias, not shown. l'ior moving the armature members I and 2 to the release position, Iprovide suitable electromagnetic means such as magnetic cores II and I! which have a common energizing winding I8.

Assuming now that the holding device in Fig. l is subjected to a translational shock applied from the right-hand side, then if the armatures I and 2 are not balanced about their respective shock will cause both of them to rotate in the same direction, that is clockwise, about their pivots. If the armatures are heavy on the latching end, the armature 2 will turn clockwise probably far enough to release its book portion 8 from engagement with the member it, but the armature I, which also tends to turn clockwise, will maintain its hook portion I in engagement with the member II to prevent release thereof. Accordingly, no movement of the member I I will occur. Similarly, a translational shock applied from the left-hand side may result in the release of the hook portion 1 of the armature i, but the hook portion 2 of the armature 2 will remain in engagement with the memher It. Thus the armatures l and 2 are jointly effective to hold the member Ill against any upward bias thereon under normal conditions and severally effective to prevent upward movement of the armature under shock conditions.

It will be apparent to those skilled in the art that my invention is not limited to the use of magnetic structures but may be carried out in other ways, as illustrated, for example, in Fig. 2..

which shows a thermally responsive shock-proof circuit breaker latching mechanism. As illustrated in Fig. 2, this mechanism is in many respects similar to the arrangement shown in Fig. 1, except that the operation of the latching elements is effected by substantially identical bimetallic strips l4 and [5 which have their lower ends firmly secured against movement. As shown in Fig. 2. the mechanism is adapted for latching a circuit breaker 16 in the closed circuit position against the bias of an opening spring 11. In this case, the free ends of the bimetallic strips l4 and I5 are respectively provided with hook type latches i8 and I9 which suitably engage a latching projection 20 on the switch operating lever 2|. The arrangement is such that both latches must be disengaged by deflection of the two bimetallic strips in opposite directions. For this purpose, the bimetallic strips are arranged with the metal having the higher thermal coeflicient of expansion on the sides toward each other so that both strips are bent outward to release the latching projection 20 when the heating current is applied. As indicated, the heating current is applied by a single operating winding 22 which is connected to a current transformer 22 in the circuit 24 controlled by the circuit breaker it.

It will be obvious to those skilled in the art that, in the embodiment of my invention illustrated in Fig. 2, the single heater coil 22 can be replaced by two similar heater coils, one around each of the bimetallic strips, or the coil or coils can be eliminated entirely by passing the heating current directly through the bimetallic strips. Since the release of the latching projection 20 is de-. pendent solely on joint movement of the thermal elements i4 and IS in opposite directions, it is obvious that the circuit breaker cannot be falsely tripped by any one mechanical shock since this cannot produce opposite movements of both of the thermal strips.

In connection with the embodiments of my invention shown in Figs. 1 and 2 where the double hook type latch is used, there should be preferably a slight slope on each of the cooperating latching surfaces, as indicated in Fig. 2, so that if one of the latch hooks becomes disengaged in consequence of a shock it will be able to re-engage itself readily. The slope angle should be small so that the latch fingers will not slide down the surfaces and release due to the force of the opening spring l1. The angle should hence besmaller than the friction angle for the engaging surfaces.

In Fig. 3, I have illustrated a fluid pressure operated latching mechanism analogous to the latching arrangement shown in Fig. 2. In the arrangement shown in Fig. 3, the latching hooks l8 and I9 are carried by .or form an integral part of two latching levers 25 and 26, respectively pivotally mounted at 21 and 28. These levers are biased for rotation in opposite directions totho latching position by suitable means such as springs 29 and 22, respectively, to cause the latching hooks l2 and II to engage opposite sides of a latching projection 24 on a member 2| pivoted at 22 and biased for movement in a predetermined direction, counterclockwise as shown. by a spring 22. The member 2| may be an operating lever or the like for any desired use such, for example, as the operating lever of a circuit breaker. V

In order to release the latchin8 hooks l2 and I9 so that the member 21 is free to move counterclockwise from the position shown to some other predetermined position which may be determined by suitable means such as a stop 24, I

provide fluid pressure operated means. As shown. this operating means comprises a cylinder 22 within which are mounted pistons 22 and 21 pivotally connected to the levers 25 and 29 through links 29 and 29, respectively. Thus, upon admission of fluid under pressure and thence by branch pipes 4| and 42 to the ends of the cylinder 25, the pistons 28 and 21 are caused to move simultaneously toward each other. This efiects rotation of the levers 25 and 22 simultaneously in opposite directions against the bias of the springs 29 and 20 so as to disengage the latching hooks l8 and I! from the latching projection 20 on the operating member 2|. Inasmuch as any one mechanical shock cannot move both of the levers 25 and 26 in opposite directions, one of the latching hooks l8 and I2 is maintained in engagement with the latchin projectlon 29 so that a false release of the operating member 2i cannot result in consequence of a mechanical shock.

In Fig. 4, I have shown an embodiment of my invention as applied to a double t flgle tripping arrangement for a circuit breaker 42. As illustrated, this tripping arrangement comprises two rotatably mounted tripping armatures 44 and is mounted to rotate about a common axis or shaft 46 between the poles 41 of a magnetic structure 49, which is arranged to be energized by a winding 49. This winding, as will be obvious to those skilled in the art, may be energized in any suitable manner either to respond to some electrical quantity of the circuit 24 controlled by the circuit breaker or to a control source for tripping the circuit breaker. as desired. The outer ends of the armatures 44 and 45 are respectively pivotally connected to a pair of substantially identical links 22 and 5!, which are in turn pivotally connected as at 52 to a switch operating rod 22. The links 52 and 5! form with their respectively associated armatures two oppositely movable cooperating toggles which are jointly operable in their thrust transmitting positions to maintain the circuit breaker in the closed circuit position. For this purpose, the lower ends of the armatures 44 and 42 are interconnected by suitable biasing means such as a spring 24, which is effective to hold the armatures against a stop I! with both toggles in an overset or thrust transmitting position somewhat over center. When the winding 49 is energized sufficiently to attract the armatures 44 and 42 whereby to rotate them in opposite directions, as indicated by the arrows 22 and 21, respectively, both of the toggles are collapsed thereby effecting the opening of the circuit breaker'in consequence of the bias due to gravity and an opening spring 22 which, as shown, is in the form of a compression spring between the pivotal point I2 and a flxed abutment I2.

With this arrangement. it will be obvious that any kind of a translational or rotational shock which would tend to move one of the toggles in the tripping direction would, at the same time, press the other toggle more firmly against the the compression spring two over-center toggles supplies torques tending to hold the armatures against the stop, never- While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Means for holding a movable circuit contog le in its holding position upon responding direction.

CLAUDE D. HAYWARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 800,538 Berry Sept. 26, 1905 926,584 Morris et a1. June 29, 1909 977,577 Wikander Dec. 6, 1910 1,052,595 Lanphier Feb. 11, 1913 1,552.561 Jacobs Sept. 8, 1925 2,353,377 Vaughn July 11, '1944 FOREIGN PATENTS Number Country Date 110,046 Austria June 25, 1928 said member in the closed circuit 

